Typical food slicers have a base with a rotatable, circular or disc-like slicing knife mounter thereon, a gauge plate for determining the thickness of the slice and a carriage for supporting the food as it is moved past the cutting edge of the knife during slicing. The cutting edge of the knife tends to dull from use and therefore a sharpener is needed to sharpen the knife to maintain a good cutting edge for efficient slicing. Sharpening stones are typically brought against the knife's cutting edge as the knife rotates in order to provide such sharpening. A variety of sharpening devices have been used in the past to provide such sharpening.
Many existing sharpening devices suffer from using complex arrangements to convert a rotational movement into two translational movements. Other existing sharpening devices require two steps, a first in which a sharpening wheel or stone is brought into contact with one side of the knife to sharpen, and a second in which a truing wheel or stone is brought into contact with the opposite side of the knife to debur the knife edge.
U.S. Pat. No. 5,591,072 which is assigned to the assignee of the present application provides a sharpening device which overcame the problem of having to move the sharpening device between an inactive or stowed position and an active or sharpening position. However, the construction provided is relatively complex and includes a large number of parts adding to the expense of manufacture.
Canadian Patent No. 630,702 describes a slicer with a knife sharpener which includes sharpening wheels which can be positioned on opposite sides of a knife for sharpening, but as mentioned above, requires the sharpener to normally be stored in an inactive position when not in use and in such inactive position the sharpening wheels are not positioned on opposite sides of the knife. Further, the sharpener requires two handles to be operated in order to sharpen the slicer knife.
Another disadvantage of known knife sharpeners is that the sharpening stones or wheels typically need to be more abrasive than the truing stones or wheels used. This requirement adds to parts cost of sharpeners and requires a more exacting manufacturing process in order to assure that the wheels of appropriate abrasiveness are placed properly during manufacture.
Further, certain food slicers are adapted for use with more than one type of slicer knife, and different knives can have different attributes such as knife edge thickness. Many existing sharpener assemblies lack the ability to account for such differences between knife types.
Accordingly, it would be desirable and advantageous to provide a relatively simple sharpener assembly which is always positioned for sharpening when attached to a food slicer. It would likewise be desirable to provide a sharpener assembly operable to provide sharpening and truing simultaneously by a single rotational motion. Further, it would be desirable and advantageous to provide a sharpener assembly configured to permit the sharpening wheel and the truing wheel to have substantially the same abrasiveness while still providing effective sharpening. Still further, a sharpener assembly which enables adjustment of the amount of sharpening which is performed would also be advantageous.